With the application of mechanistic model (RICAM 1.3, RIce growth Calendar Model), this paper simulated the rice development and its yield formation under different climatic conditions at multi-locations of Asia. A three-stage Beta model (3s-Beta) was developed to predict the flowering stage of rice and to describe its three successive phases of photo-thermal response, i. e., basic vegetative phase, photoperiod-sensitive phase, and post photoperiod-sensitive phase. The 1980-1989 multi-location data of Morioka (Japan, 39°43′N), Nanchang (China, 28°36′N) and Los Banos (Philippines, 14°11′N) were used to verify the suitability of the model in studying ecosystem change. Comparisons of simulated results with observed data showed that this model could generally predict the eco-physiological processes of rice, and performed very well over a wide range of environments.